Fujitsu Corporation

Shoji Yoshida

Tooru Matsumoto

Makoto Takakuwa

Akio Morimoto

Yoshihiro Shimizu

An optical amplifying device disposed on a transmission path of a WDM signal includes an optical amplifier amplifying the WDM signal, a detecting unit detecting a change in a transmission wavelength count contained in the WDM signal and/or a change in light receiving level of the optical amplifier, a measuring unit measuring an optical signal to noise (SN) ratio of the WDM signal outputted from the optical amplifier, an update unit updating a reference value for evaluating the measurement value of the optical SN ratio obtained by the measuring unit when the detecting unit detects the change, a judging unit judging whether or not the measurement value deviates from an allowable range based on a reference value, and an output unit outputting an error of the optical amplifier if the measurement value deviates from the allowable range.

Optical amplifying device

An optical transmission system includes an optical wavelength branching unit that shifts a wavelength transmission band in the short-wavelength or long-wavelength directions based on a branching filter operation temperature, and performs a branching operation on a wavelength-multiplexed signal. A reception transponder performs decoding on an error correction code. An error correction monitoring unit gathers an error correction amount upon which a branching filter temperature control unit sets the branching filter operation temperature. A transmission transponder performs encoding on an error correction code. An optical wavelength combining unit shifts the wavelength transmission band in the opposite direction from the shifting direction based on a combining filter operation temperature, to perform a combining operation on optical signals and output a wavelength-multiplexed optical signal. A combining filter temperature control unit sets the combining filter operation temperature based on the error correction amount sent from the optical reception device.

Optical transmission system

The present invention relates to a serial/parallel converter circuit with uncertainty removing function. The object of the invention is to offer that signals can be instantaneously rearranged in the same data arrangement as that of original parallel signals prior to a parallel to serial conversion. The serial/parallel converter circuit is constituted of a serial/parallel converter unit for converting a serial signal once subjected to a parallel to serial conversion into parallel signals; a parallel/serial converter unit for converting the parallel signals converted by the serial/parallel converter unit into a serial signal; a comparing and judging unit for judging whether the serial/parallel converter unit has converted at a predetermined timing operation, by comparing the serial signal from the parallel/serial converter unit with the serial signal inputted to the serial/parallel converter unit; and correcting unit for correcting the parallel signals from the serial/parallel converter unit when the serial/parallel converter unit has not converted at a predetermined timing operation, based on the result from the comparing and judging unit.

Serial/parallel converter circuit with uncertainty removing function

An error suppression system suppresses an error of a data sequence generated in a transmission path between a transmitting terminal and a receiving terminal. The error suppression system includes a data coding circuit in the transmitting terminal for inserting a known bit at a predetermined position of the data sequence and for carrying out a difference logic conversion with respect to the data sequence, a differential coding circuit in the transmitting terminal for carrying out a sum logic conversion with respect to the data sequence which is received from the data coding circuit, a differential decoding circuit in the receiving terminal for carrying out a difference logic conversion with respect to the data sequence received from the differential coding circuit via the transmission path, and a data decoding circuit in the receiving terminal for carrying out a sum logic conversion with respect to the data sequence received from the differential decoding circuit and for restoring the known bit at the predetermined position of the data sequence.

Growing community of inventors

Kawasaki, Japan

Shoji Yoshida